[SmartCat]

While watching some off-road videos on Youtube, I found this interesting 6 wheel drive Land Rover Defender video -

http://www.youtube.com/watch?v=XvCl3WzieG4

Does 6 wheel drive offer any significant advantages over an equivalent 4WD vehicle, all things being equal (driver skills, tyres, off-road "features")? More driven wheels, the better? Why don't we have more manufacturers offering 6 wheels on their off-road SUVs?

The most famous 6x6 SUV I guess is the Merc G63 AMG 6x6 -




My observation (looking at videos) is that since the two rear wheels being too "close" to each other, these vehicles don't seem to go significantly farther than 4WD in slushy conditions. That is, both the second and third of wheels are in the slush most of the time, and the extra row of wheels too keep spinning.

I think 6x6 Armoured Personnel Carriers are better designed to go off-road! If the first 2 sets are wheels are stuck in sand/slush, then the probability of third set of wheels being on grippier ground is higher - because all 3 sets of wheels are almost equidistant from one another.

[Tejas@perioimpl]

Six wheels also give better weight distribution since these are primarily heavy goods movers.

[dhanushs]

Originally Posted by smartcat

Why don't we have more manufacturers offering 6 wheels on their off-road SUVs?

Well, as for the answer to this, the effects of the added mechanicals (Diffs, drive shafts, hubs, etc.. etc.. ) will amount to:
High production costs
Increased maintenance costs
Increased drive-train loss
Lower fuel efficencies.
Increased length
etc...

And, the benefits
(Increased traction with two wheels, and increased load carrying capacity) might not add up to match the above??

[thumpingheart]

The advantages will definitely reflect in hard core off roading, but in more sort of a army/fire fighters/medi-evac or extreme emergency situations I guess. There will be more traction and they will provide better articulation most times on really undulating terrain. For most really extreme "GET ME OUT OF THIS SITUATION" type scenarios it will fare well.

But overall it doesn't make sense for a mass production or public usage type scene. First of all, like dhanushs pointed out, the disadvantages stack up higher than advantages. The cost of buying and maintaining will be extremely high and to carry out maintenance and repair it will be extremely complex. And I'm pretty sure the hardcore off road guys will prefer a 4WD over a 6WD for their hobby.

They are in love with their weapon of choice - Gypsy, CJs, Willis', Thar, Jeep etc. Its not only completing the circuit but doing it in their car. 4WD comes with its own advantages and disadvantages but the enthusiasts like to work with them both. I am sure there are certain enthusiasts who do their off roading in 6WDs and bigger trucks and what not, which is a scene in a few countries around the world. But that is a different genre all together.

Certain people may have the money and patience to work with 6WDs for hobby off roading but on a general mass production type deal no manufacturer will start building 6WD machines. Of course Mercedes is producing the G-Wagon 6WD but that's a niche market with mostly super rich people buying it as a toy rather than to do real off roading.

[SirAlec]

major disadvantage of 6x6 would be
1. high maintenance, extra prop shaft, extra diff, extra brakes, extra hub.
2. higher cost. i mean you have to also replace two extra wheel when its worn out.
3. Now if you are a money bag but still want to go for 6x6 then major disadvantage of 6x6 over 4x4 would be agility and maneuverability.

ADvantage would be.
1. more payload.
2. extra sets of powered wheels would be helpful right.
3. comfort and less bouncy if axle are mounted on tandem setup.

[shankar.balan]

What can you do with a 6x6?
Climb Mount Kanchenjunga single handed?
Most people would be happy enough with a good tough, reliable 4x4. 6x6 is serious overkill for normal off road work.
I guess one may need it only if one is say, a Nat Geo photographer, habitually driving the terrain less traversed!

[Sandman689]

I have always admired Russian 6X6 and 8X8 trucks. They have always seemed (and perhaps are) more capable than regular 4X4s. I personally think that a lot more depends on these vehicles than 4X4s used OTRs so they have to be more capable.

[GTO]

Check this one out from Mumbai (Link to OLX ad). Though the odds are, it's a 6x4 (or 6x2) and not a 6x6.

[alpha1]

More wheels should also improve the pressure distribution on the soil/land.
Like the caterpillar or the continuous tracks reduce the pressure on the ground to a huge extent and that helps it in delicate soil/wet/slush conditions.

[Amrik Singh]

Normally 4WD are good enough to carry us to places difficult to reach otherwise.

In my opinion, such places where 4WD cannot reach and 6x6 are required are better to be left alone and preserved as nature has created it.

Amrik Singh

[jinojohnt]

Unless the shocks have a very large travel, won't 2 wheels always be in the air (without touching the ground) when the 6X6 vehicle is over rough terrain?

[Kaumad]

Wow, this one takes "multi-brand" to a new level.
Ford and H2 in the front, Jeep and Toyota at the back. Why, he has got a new 'willy' too.

[ex670c]

Hi Guys,

In a 4x4 Transfer Case there is a 50:50 split between Front & Rear axles.

But in a 6x6, the Transfer Case splits the torque 33:66 between Front & Rear Axles.

The advantages of a 6x6 (already mentioned in earlier posts)

1) Better load carrying capacity, for a smaller vehicle
2) More Traction

The disadvantages are
1) Difficult Transmission (Transfer Case) for smaller 6x6 (G-Wagen/JEEP/Dodge/Defender)

2) Intricate rear Suspension (Short Radius Arms and coil Springs or elliptical leaf springs/Inverted Leaf Springs.

The Trucks are easier since they have a much bigger chassis.

The Military APC's use a different 6x6, which has a equal Wheel Base, between all three axles, and they are Independent Suspension.

Regards,

Arka

[GTO]

Originally Posted by ex670c

But in a 6x6, the Transfer Case splits the torque 33:66 between Front & Rear Axles.

Or 30:40:30 with this beast of a Mercedes

The video is far out!

https://www.youtube.com/watch?v=QaNk116b2kw

[asivan]

6x6's are generally preferred in extremely tough terrains as well as on the basis of the GVW of the vehicle. Military APC's as well as MPV's are generally wanted to have very high requirements of traction as well as protection (armour protection increases weight). Hence, the 6x6 solution works much better.

And since these vehicles are much higher in terms of cost as well as low production volume, it makes commerical sense to follow the design philosophy. Commercial vehicles will never have the same requirements.